Question: The sites with NPCs. Are they doable? What I mean is that with a Cruiser or BS, could I take them or is it a lost cause? Are they beyond level 4 security missions?
I dont have a great answer for that, other than drifter and sleeper NPCs (usually wormholes) are significantly harder. check eve uni’s wiki for more detail/ship suggestions for specific site names
If it helps…Sleeper Caches (which apart from a few small exceptions) only spawn in K-Space and not in Wormholes
the 98.8% scanning you have got to I suspect could be a Superior Sleeper Cache - which you need a scan probe strength greater than 110 from memory (might be 105) but that is a level 5 difficulty to scan down.
Standard and limited sleeper cache’s require a lower scan strength to scan down and are only lvl 4 difficulty.
If you want to run those sites - they are do-able (to a certain extent) in just a frigate if you follow guides and pilot carefully - EVE Uni has walkthroughs on their site and Nth Dimensional on YouTube has good videos for these sites (https://www.youtube.com/@nthdimensional/videos)
Any sites with the name containing XXXX-PirateFaction-Covert Research Facility are Pirate Ghost Sites and there’s some good reading here (these will explode if you fail the hack and if you take too long rats will spawn and smash you): https://wiki.eveuniversity.org/Ghost_Sites
good luck and keep exploring as these sites are awesome and exploration is a great type of play